The present invention relates to a device useful in the treatment of emphysema and other diseases or disorders of the human or animal lung.
Emphysema is a disease of the lung caused primarily by prolonged smoking, although not exclusively thereby. It is an unrelentless, intractable and debilitating process. Emphysema is defined as an abnormal permanent enlargement of the air spaces distal to the terminal bronchioles, accompanied by destruction of their walls without obvious fibrosis. In this context, destruction means non-uniformity in the pattern of respiratory, airspace enlargement; orderly appearance of the acinus is disturbed and may be lost.
Emphysema causes a physiological loss of lung elastic recoil, which decreases expiratory airflow by loss of driving pressure and premature airway closure from reduced airway traction. The effect of this is that the alveoli become hyper-inflated without there being any real exchange of air with the outside. Therefore the patient begins to feel starved of oxygen and so attempts to breathe more deeply. In breathing more deeply, the effects are exacerbated.
Not only are those individual alveoli which have a block in their respective bronchial tubules affected, but also neighbouring alveoli, perhaps in other regions of the lung, which may otherwise be perfectly serviceable, become affected because the hyper-inflated alveoli pressurise neighbouring alveoli and prevent them from expanding fully. There is, of course, a relatively fixed “exchange” volume of an individual's lung, that is to say, the difference between the expanded volume and the deflated volume. Emphysema reduces the exchange volume because undeflated alveoli occupy that space. Consequently, the only recourse available to the patient is to increase the expanded volume, thereby resulting in the barrel chest symptomatic of emphysema sufferers.
The major therapeutic modalities currently available consist of bronchodilator and anti-inflammatory drugs, directed at decreasing airway resistance, and antibiotics to treat acute and chronic infection. Supplemental oxygen therapy for the hypoxaemic patient improves exercise performance and improves survival in patients with cor pulmonale. Despite all available medical therapies, the course of the disease is one of progressive limitation, increasing dyspnoea and significant increase in overall mortality.
It has long been realised that full lung volume is more than enough for survival in most circumstances and that a person can survive quite satisfactorily with only one lung, for example. Heterogenous distribution of emphysema, together with the lack of pulmonary blood flow to those areas have made lung volume reduction surgery a logical option. Removal of parts of the lung affected by emphysema permits unaffected areas to become operative again and so enable a better quality of life for the patient. Clearly, however, such invasive procedures are of a very serious nature and some patients will not, in any event, be in a sufficiently strong condition to accept the trauma of such procedures. Primarily, the basic relief for emphysema sufferers is inactivity, on the one hand, and breathing pure oxygen, on the other.
Emphysema is a distressing condition affecting a relatively large proportion of the population, and a more effective and less traumatic treatment is required.
On a different matter, other lung conditions sometimes lead to bleeding into the lung. A patient having this condition feels movement of the blood caused by airflow in the lung during breathing, and perceives the blood as a foreign body and irritant. The patient coughs in an attempt to dislodge the perceived foreign body. Coughing blood, of course, is sometimes the first warning of a more serious disease or condition, but once that is realised, there is no benefit in such bleeding. Moreover, in such conditions where the lung might heal itself and subsequently stop bleeding, or indeed simply where the bleeding needs to be confined, the coughing reaction, which is almost impossible to resist, does not help the situation at all, and merely spreads the blood to other areas of the lung.
U.S. Pat. No. 5,382,261 discloses a vessel occluder for providing permanent occlusion of a vessel in a person by use of a flexible closure member attached to at least one radially expandable stent. The occluder does not have barbs or anchors or a stent.
DE-U-9205797 discloses a self expanding ‘meshbasket’ for the occlusion of human hollow organs. The invention is directed to female contraceptive devices and addresses the problem of remaining in place. The device may also find application in embolism therapy and vascular occlusion.
WO-A-9532018 discloses a body passageway closure for use in the occlusion of various passageways within the body, with particular application for the occlusion of blood vessels.
Therefore it is an object of the present invention to provide a method of treatment of certain lung conditions or diseases and to provide a device for such treatment.